#pragma once
#include "stdafx.h"
#include <stdexcept>
#include <cfloat>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string>
#include <string.h>



#include "StringData.h"
#include "inline_decls.h"
const int BufferMaxSize = 64 * 1024 * 1024;

/* Note the limit here is rather arbitrary and is simply a standard. generally the code works
with any object that fits in ram.

Also note that the server has some basic checks to enforce this limit but those checks are not exhaustive
for example need to check for size too big after
update $push (append) operation
various db.eval() type operations
*/
const int BSONObjMaxUserSize = 16 * 1024 * 1024;

/*
Sometimes we need objects slightly larger - an object in the replication local.oplog
is slightly larger than a user object for example.
*/
const int BSONObjMaxInternalSize = BSONObjMaxUserSize + ( 16 * 1024 );
template <typename Allocator>
class StringBuilderImpl;

class TrivialAllocator { 
public:
	void* Malloc(size_t sz) { return malloc(sz); }
	void* Realloc(void *p, size_t sz) { return realloc(p, sz); }
	void Free(void *p) { free(p); }
};

class StackAllocator {
public:
	enum { SZ = 512 };
	void* Malloc(size_t sz) {
		if( sz <= SZ ) return buf;
		return malloc(sz); 
	}
	void* Realloc(void *p, size_t sz) { 
		if( p == buf ) {
			if( sz <= SZ ) return buf;
			void *d = malloc(sz);
			if ( d == 0 )
				throw std::runtime_error( "out of memory StackAllocator::Realloc" );
			memcpy(d, p, SZ);
			return d;
		}
		return realloc(p, sz); 
	}
	void Free(void *p) { 
		if( p != buf )
			free(p); 
	}
private:
	char buf[SZ];
};

template< class Allocator >
class _BufBuilder {
	// non-copyable, non-assignable
	_BufBuilder( const _BufBuilder& );
	_BufBuilder& operator=( const _BufBuilder& );
	Allocator al;
public:
	_BufBuilder(int initsize = 512) : size(initsize) {
		if ( size > 0 ) {
			data = (char *) al.Malloc(size);
			if( data == 0 )
				throw std::runtime_error("out of memory BufBuilder");
		}
		else {
			data = 0;
		}
		l = 0;
	}
	~_BufBuilder() { kill(); }

	void kill() {
		if ( data ) {
			al.Free(data);
			data = 0;
		}
	}

	void reset() {
		l = 0;
	}
	void reset( int maxSize ) {
		l = 0;
		if ( maxSize && size > maxSize ) {
			al.Free(data);
			data = (char*)al.Malloc(maxSize);
			if ( data == 0 )
				throw std::runtime_error(  "out of memory BufBuilder::reset" );
			size = maxSize;
		}
	}

	/** leave room for some stuff later
	@return point to region that was skipped.  pointer may change later (on realloc), so for immediate use only
	*/
	char* skip(int n) { return grow(n); }

	/* note this may be deallocated (realloced) if you keep writing. */
	char* buf() { return data; }
	const char* buf() const { return data; }

	/* assume ownership of the buffer - you must then free() it */
	void decouple() { data = 0; }

	void appendUChar(unsigned char j) {
		*((unsigned char*)grow(sizeof(unsigned char))) = j;
	}
	void appendChar(char j) {
		*((char*)grow(sizeof(char))) = j;
	}
	void appendNum(char j) {
		*((char*)grow(sizeof(char))) = j;
	}
	void appendNum(short j) {
		*((short*)grow(sizeof(short))) = j;
	}
	void appendNum(int j) {
		*((int*)grow(sizeof(int))) = j;
	}
	void appendNum(unsigned j) {
		*((unsigned*)grow(sizeof(unsigned))) = j;
	}
	void appendNum(bool j) {
		*((bool*)grow(sizeof(bool))) = j;
	}
	void appendNum(double j) {
		*((double*)grow(sizeof(double)))= j; 
	}
	void appendNum(long long j) {
		*((long long*)grow(sizeof(long long))) = j;
	}
	void appendNum(unsigned long long j) {
		*((unsigned long long*)grow(sizeof(unsigned long long))) = j;
	}

	void appendBuf(const void *src, size_t len) {
		memcpy(grow((int) len), src, len);
	}

	template<class T>
	void appendStruct(const T& s) {
		appendBuf(&s, sizeof(T));
	}

	void appendStr(const StringData &str , bool includeEndingNull = true ) {
		const int len = str.size() + ( includeEndingNull ? 1 : 0 );
		memcpy(grow(len), str.data(), len);
	}

	/** @return length of current string */
	int len() const { return l; }
	void setlen( int newLen ) { l = newLen; }
	/** @return size of the buffer */
	int getSize() const { return size; }

	/* returns the pre-grow write position */
	inline char* grow(int by) {
		int oldlen = l;
		l += by;
		if ( l > size ) {
			grow_reallocate();
		}
		return data + oldlen;
	}

private:
	/* "slow" portion of 'grow()'  */
	void NOINLINE_DECL grow_reallocate() {
		int a = 64;
		while( a < l ) 
			a = a * 2;
		if ( a > BufferMaxSize ) {
			std::stringstream ss;
			ss << "BufBuilder attempted to grow() to " << a << " bytes, past the 64MB limit.";
			throw std::runtime_error(ss.str().c_str());
		}
		data = (char *) al.Realloc(data, a);
		if ( data == NULL )
			throw std::runtime_error(  "out of memory BufBuilder::grow_reallocate" );
		size = a;
	}

	char *data;
	int l;
	int size;

	friend class StringBuilderImpl<Allocator>;
};

typedef _BufBuilder<TrivialAllocator> BufBuilder;

/** stringstream deals with locale so this is a lot faster than std::stringstream for UTF8 */
template <typename Allocator>
class StringBuilderImpl {
public:
	static const size_t MONGO_DBL_SIZE = 3 + DBL_MANT_DIG - DBL_MIN_EXP;
	static const size_t MONGO_S32_SIZE = 12;
	static const size_t MONGO_U32_SIZE = 11;
	static const size_t MONGO_S64_SIZE = 23;
	static const size_t MONGO_U64_SIZE = 22;
	static const size_t MONGO_S16_SIZE = 7;

	StringBuilderImpl() { }

	StringBuilderImpl& operator<<( double x ) {
		return SBNUM( x , MONGO_DBL_SIZE , "%g" );
	}
	StringBuilderImpl& operator<<( int x ) {
		return SBNUM( x , MONGO_S32_SIZE , "%d" );
	}
	StringBuilderImpl& operator<<( unsigned x ) {
		return SBNUM( x , MONGO_U32_SIZE , "%u" );
	}
	StringBuilderImpl& operator<<( long x ) {
		return SBNUM( x , MONGO_S64_SIZE , "%ld" );
	}
	StringBuilderImpl& operator<<( unsigned long x ) {
		return SBNUM( x , MONGO_U64_SIZE , "%lu" );
	}
	StringBuilderImpl& operator<<( long long x ) {
		return SBNUM( x , MONGO_S64_SIZE , "%lld" );
	}
	StringBuilderImpl& operator<<( unsigned long long x ) {
		return SBNUM( x , MONGO_U64_SIZE , "%llu" );
	}
	StringBuilderImpl& operator<<( short x ) {
		return SBNUM( x , MONGO_S16_SIZE , "%hd" );
	}
	StringBuilderImpl& operator<<( char c ) {
		_buf.grow( 1 )[0] = c;
		return *this;
	}

	void appendDoubleNice( double x ) {
		const int prev = _buf.l;
		const int maxSize = 32; 
		char * start = _buf.grow( maxSize );
		int z = sprintf_s( start , maxSize , "%.16g" , x );
		assert( z >= 0 );
		assert( z < maxSize );
		_buf.l = prev + z;
		if( strchr(start, '.') == 0 && strchr(start, 'E') == 0 && strchr(start, 'N') == 0 ) {
			write( ".0" , 2 );
		}
	}

	void write( const char* buf, int len) { memcpy( _buf.grow( len ) , buf , len ); }

	void append( const StringData& str ) { memcpy( _buf.grow( str.size() ) , str.data() , str.size() ); }

	StringBuilderImpl& operator<<( const StringData& str ) {
		append( str );
		return *this;
	}

	void reset( int maxSize = 0 ) { _buf.reset( maxSize ); }

	std::string str() const { return std::string(_buf.data, _buf.l); }

	int len() const { return _buf.l; }

private:
	_BufBuilder<Allocator> _buf;

	// non-copyable, non-assignable
	StringBuilderImpl( const StringBuilderImpl& );
	StringBuilderImpl& operator=( const StringBuilderImpl& );

	template <typename T>
	StringBuilderImpl& SBNUM(T val,int maxSize,const char *macro)  {
		int prev = _buf.l;
		int z = sprintf_s( _buf.grow(maxSize) , maxSize , macro , (val) );
		assert( z >= 0 );
		assert( z < maxSize );
		_buf.l = prev + z;
		return *this;
	}
};

typedef StringBuilderImpl<TrivialAllocator> StringBuilder;
typedef StringBuilderImpl<StackAllocator> StackStringBuilder;